连续刚构桥动力特性参数识别与有限元模型修正

Dynamic Characteristic Parameters Identification and Finite Element Model Updating for Continuous Rigid Frame Bridge

以东营黄河公路大桥——大跨预应力混凝土连续刚构桥为对象,首先利用ANSYS建立了全桥的三维有限元模型并进行了理论模态分析;并应用频率分解方法(FDD)和特征系统实现算法(ERA)分析了该桥所安装的健康监测系统采集的加速度响应数据,进行了桥梁动力特性参数识别;最后,在所建立的初始有限元模型和识别的实际桥梁动力特性参数的基础上,采用模型修正的方法,得到了该桥修正的有限元模型。研究结果表明,通过该桥监测系统采集的加速度数据可以较好地识别其模态参数,所识别的模态参数可作为结构动力特性修正的依据;修正后的有限元模型能更真实地反映结构的动力特性,模型修正的结果较好地反映了实际桥梁的物理特性。该模型可以作为该桥梁长期健康监测与状态评估的基准模型。

A three dimensional FE model of a long-span prestressed continuous rigid frame bridge--Dongying Yellow River Bridge was constructed and the modal analysis was performed using ANSYS.The real dynamic characteristic parameters of this bridge were identified by using the Frequency Domain Decomposition （FDD） method and the Eigensystem Realization Algorithm （ERA） method from the acceleration data recorded by the monitoring system on this bridge. A refined FE model of this bridge was obtained by updating the initial FE model using the identified modal parameters. The research results show that （1） the modal parameters of this bridge can be identified with good accuracy from the acceleration responses collected by the monitoring system, and the identified modal parameters can be used to update the initial FE model; （2） the updated FE model can accurately reflect the structural dynamic characteristics of the bridge, and the updated physical parameters have good connectivity with the physical condition of the bridge. It is therefore concluded that the updated FE model can be a reliable benchmark model for long-term health monitoring and condition assessment of this bridge.